<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="vue/vue.js" charset="utf-8"></script>

</head>
<body>

<div id="app">
    <input type="button" value="添加" @click="add">
    <br>
    <ul>
        <li v-for="(value,index) in arr">{{value}}  {{index}}</li>
    </ul>

</div>

<script>
    new Vue({
        el:'#app',
        data:{
           arr:['a','b','v','c'],
        },
        methods:{
            add:function () {
                this.arr.push('mm')
            }
        }
    })
</script>

</body>
</html>